Noises / Roaring / surging - United Bimmer Community

**MCBEAMER** · 07-20-2008, 04:32 PM

Issue#1:Sorry to jump on board with another question, instead of helping to resolve one... I too have a roaring issue coming that seems to be coming from the back half of my 97 328is... My noise is speed related as I speed up the noise increases and as another post indicated it sounds like a flat spot on a tire... At this point I have only visually inspected the tires to check for bald spots or broken cords... I plan this afternoon to lift the car and do a better inspection... any idea how to check bearings without major disassembly?

Issue #2: I noticed yesterday when driving that the engine has developed a surge... going steadly down the road at approx 2k rpm's the engine with increase lightly(up & down)... When beginning to pull out the engine is sputtering and seems hesitant... still has power after low idle but the issue is still detectable....

Thanks for any leads to make my afternoon more productive... Thanks in advance and I really appreciate this forum and the help it give us hands on BMW owners...

M

**3050rpm** · 07-20-2008, 04:39 PM

A couple of thoughts, see if you have a dented, and hence out-of-round rear wheel. As for the surging, it could be your 02 sensor is on its way out, causing it to "hunt" for the proper emissions setting.

**MCBEAMER** · 07-21-2008, 05:42 PM

I did a better inspection under the hood and found a vaccum line broken... after replacing it the connection the car seems to be smooth again... I'll know for sure after a longer test drive...

I found also a front wheel hub that had a worn bearing... I replaced the entire hub assembly this afternoon and altho better I still have more roaring... I starting to supect my tires may be contributing to this as well... I plan to pull the other wheels for a closer look...

Thanks for the ideas and if the sensor decides to die... I should get a engine light and a code...?

M

**3050rpm** · 07-22-2008, 10:27 PM

Yeah, wheel bearings should be checked, as well as suspension bushings, front and rear.

Normally when the O2 sensor goes you should get a check light and a code, but my last go around with a sensor needing replacement didn't generate the light although the car was running crappy. The fact that it didn't pass emissions inspection was also a tipoff. Took it to my service guy and he ran the diagnostics and the sensor was shot, or on its way out. New sensor, car ran great, passed inspection no problem.